feat: integrate stock BAR queue reader and Lua observer

[EHotwagner]

Summary

• integrate the accepted stock Recoil 2639 native queue reader with the accepted stock observer Lua content
• preserve the frozen stock queue contract, protocol projection, and golden vectors byte for byte
• retain the existing legacy full tuple route while adding the separately identified stock observed queue route

Verification

• fresh plugin only build against pristine Recoil 2639eedac7d1fd67d793ec93ebd27f014f336a14: PASS
• native focused suites: 49/49 PASS (26 live control, 5 stock queue reader, 18 tactical native state)
• Lua observer suite: 14/14 PASS
• stock Lua 5.1 float ABI vectors: PASS
• stock queue contract vectors: PASS
• arm coverage: 66/66 wired
• shell syntax and all 15 configured skip stubs: PASS
• BUILD.md structural validation: 10 steps, all expected substrings present
• deterministic Lua package: c7d6b583a954e7c2b0fdbb9c697355aaf1d2a1cd24049c3d30b9e01dfdd99d4c
• fresh plugin artifact: d08be63906849bd9e83f758d80e42b78dec96c45f0dc889073cb57e9c7e0137a

Qualification boundary

This is a source integration and preflight result. The six native journeys remain open. The optional custom factory replacement route remains historically available and does not qualify the stock route.

The repository hosted workflow must still run its buf and Python jobs. Conditional self hosted build and live acceptance jobs remain subject to the repository runner variable and root controlled admission.